1. Field of the Invention
The present invention relates to an image reading device provided with multiple pixel arrays, and a method for driving the image reading device.
2. Description of the Related Art
In recent years, there is known a solid-state image sensing device provided with pixel arrays arranged in the vertical direction, with each of the pixel arrays (hereinafter called as “pixel rows”) being formed by arranging a number of pixels in the horizontal direction. The solid-state image sensing device is configured to acquire a color image by moving the pixel rows in the vertical direction with respect to a document. For instance, Japanese Unexamined Patent Publication No. 2002-142078 discloses a solid-state image sensing device capable of acquiring a monochromatic image at a high sensitivity and a high speed, as well as a color image, by transferring signal charges generated in the first through the third pixel rows having blue, green, and red filters, using a CCD register.
In recent years, there is also known a solid-state image sensing device for reading out image data obtained by multiple pixel rows with use of a readout circuit provided in common with respect to the pixel rows, without using a CCD register. The solid-state image sensing device is advantageous in reducing the pitch of the pixel rows in the vertical direction by the size corresponding to a CCD register.
In the above-mentioned solid-state image sensing device, the pitch of the pixel rows in a vertical direction is restricted. Further, it is required to control a readout timing of image data from the pixel rows by changing a vertical resolution while controlling the pitch of the pixel rows in order to read out image data without color displacement.